Light splitting systems

Sayama K, Mukasa K, Abe R, Abe Y, Arakawa H (2002) Photo-catalytic water splitting system into H2 and 02 under visible light irradiation mimicking a Z-scheme mechanism in photosynthesis. Solar Light Energy Conversion Team, Photoreaction Control Research Center, Advanced Industrial Science and Technology (AIST), Ibaraki, Japan... 

A New Photocatalytic Water Splitting System under Visible Light Irradiation Mimicking a Z-Scheme Mechanism in Photosyn thesis. See Entry 23 above. 349... 

Light Harvesting Units in Artificial Water Splitting Systems... 

The diverged infrared radiation from the input slit is directed to a parabolic mirror and returned toward the splitting system (prism or gird). Depending on the type of optical principle, the parallel reflected infrared light passes through the prism or split by the diffraction gird. It is then reflected back by a plane mirror at the same parabolic reflector for the Littrow monochromator or at a second parabolic reflector for the Ebert monochromator. After this, the monochromic infrared radiation is directed to the output slit. 

The latest systems appear to work under visible light illumination without a noble metal-based H2 and/or O2 catalyst There have been reported photocatalysts such as delafossite CuFe02, without a separate H2 or O2 catalyst, or In/NiAra-oxides coated with NiO, or RUO2 for visible-light activated water-splitting processes. However, all reported water-splitting systems are controversial and require confirmation [3]. 

Photoinitiators. Derivatives of benzoin and benzil are added in amounts of 1-3% as photoinitiators in UV-curing systems. These have differing effectiveness in the UP systems [2.99], Special initiators are available for pigmented systems. The UV light splits them into radicals which in turn initiate polymerisation. The UV radiation is generated using superactinic fluorescent lamps and/or high-pressure mercury vapour lamps [2.109]. 

A mathematical model of PSII reaction centre containing 6 different states of the complex is represented. A possibility for cycling of electrons around PSII is included. The model describes dark-light-dark transients in fluorescence, including the tip effect. The mechanism of fluorescence quenching and regulation of the PSII activity based on the futile cycle or pheophytin redox potential shifts were studied. In the first case the tip effect is present in the fluorescence induction but it is absent in the second case. Fluorescence induction curves are sensitive to the rate of electron donation from the water-splitting system which can be controlled either by the redox state of the donor or by the rate constant of electron donation. 

ATP synthesis as well as light induced ATPase activity. This means that photll drives enzymatic activity of CF1 without showing a correlation with nucleotide exchange as found with PMS mediated electron transport through photl (J.Schumann, H.Strotmann, 1981). We conclude from this that protons from the water splitting system are not the regulative ones discussed in our model. 

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